Chapter 20: Sheet-Metal Forming

Example 20.1, Deep Drawing, Page No. 672

from math import log

#variable declaration
le=0.3;
wd=-0.16;

#calcualtion
l_l0=1+le;
w_w0=1+wd;
R=log(1/w_w0)/log((w_w0)*l_l0);

#result
print('\nLimiting ratio = %g')%(R);

Limiting ratio = 1.98104

Example 20.2, Forming Limit Criteria, Page No. 675

#variable declaration
d=0.1;
mj_d=0.18;
mn_d=0.08;

#calculation
e1=(mj_d-d)/d;
e2=(mn_d-d)/d;

#result
print('\nMajor Strain = %g percent \nMinor Strain = %g percent')%(e1*100,e2*100);

Major Strain = 80 percent 
Minor Strain = -20 percent